In a buffer solution containing equal concentration of $B^{-}$ and $HB,$ the $K_b$ for $B^{-}$ is $10^{-10}.$ The $pH$ of the buffer solution is:

$A$ buffer solution is prepared by mixing $0.2 \ M \ NH_4OH$ and $1 \ M \ NH_4Cl$. What is the $pH$ value of the buffer solution? (Given $pK_b = 4.744$)

$A$ buffer solution contains $100 \ mL$ of $0.01 \ M \ CH_3COOH$ and $200 \ mL$ of $0.02 \ M \ CH_3COONa$. If $700 \ mL$ of $1 \ M \ NaCl$ is added,what are the $pH$ values before and after the addition? $(pK_a = 4.74)$

Find the value of $\frac{[NaCN]}{[HCN]}$ given the $pH$ of the buffer solution of $NaCN$ and $HCN$ is $9.3$ and $K_a$ of $HCN$ is $5 \times 10^{-10}$.

Find $pH$ of the resultant solution formed by the addition of $500 \ mL$ $0.1 \ M$ $Ba(OH)_2$ and $500 \ mL$ $0.6 \ M$ $NH_4Cl$ in $1 \ L$ pure $H_2O$ at $25 \ ^oC$ (Use $\log \ 2 = 0.3$,$\log \ 3 = 0.5$,$\log \ 5 = 0.7$,$K_b(NH_3) = 10^{-5}$)

If a small amount of sodium acetate is added to an equimolar mixture of sodium acetate and acetic acid,the $pH$ of the resulting solution will .......